1. Field of the Invention
The invention relates in general to a substrate exposure apparatus and method, and more particularly, to a substrate exposure apparatus and method that does not require a photomask for transferring a pattern to the photoresist.
2. Description of the Related Art
Photolithography process is one of the crucial steps in the print circuit board, the substrate and the semiconductor fabrication process. In wafer fabrication, the patterned and doped regions for each thin film layer are determined by photolithography process. Additionally, the formation of metal film patterns in the print circuit board and the substrate are determined by the photolithographic process. For each one, the photomask must be well prepared. In the photolithographic process, after some preparation procedures, the photomask is coated on the substrate, and then a soft baking and a hard baking processes are further performed. After the photoresist on the wafer is cured, the steps of exposure and development are performed to transfer the pattern of the photomask to the photoresist.
Referring to FIG. 1, a conventional photolithography process that uses a contact mode photomask to transfer the pattern to the photoresist is schematically shown. A substrate 100, on which circuit, dielectric layer, dielectric pattern or conductive layer may have been formed, is provided. A photoresist 102 is formed on the substrate 100. A photomask 110 is disposed on the photoresist 102. To protect the surface of the photomask 110, a protect film 104 is placed between and separates the photomask 110 and the photoresist 102. The protect film 104 is in contact with both the surface of the photomask 110 and the photoresist 102. By radiation of a light source 112, an exposure step is performed on the photoresist 102, so that the pattern of the photomask 110 is transferred to the photoresist 102.
The conventional contact mode photomask 110 includes formation of a patterned blocking layer 108 on a surface of a transparent substrate 106. To protect the photomask 110, the protect film 104 sandwiched between the photomask substrate 106 and the photoresist 102 is in contact with both surfaces of the photomask substrate 106 and the photoresist 102. The patterned blocking layer 108 of the photomask 110 blocks the light source 112 to determine the pattern on the photoresist 102 to be radiated.
Referring to FIG. 2, a conventional photolithography process using a non-contact mode photomask to transfer a pattern to a photoresist is schematically shown. A substrate 200 on which a photoresist 202 is formed is provided. Circuits, dielectric layers, dielectric patterns or conductive layers may have been formed on the substrate 200. A photomask 210 is located above the photoresist 202. A lens set 214 is disposed between the photomask 210 and the photoresist 202. By radiation of a light source 212, the photoresist 202 is exposed, and the pattern of the blocking layer 208 on the photomask 210 is transferred as the pattern 216 on the photoresist 202.
The conventional non-contact mode photomask is constructed by forming the patterned blocking layer 208 on a transparent substrate 206. The patterned blocking layer 208 on the transparent substrate 206 blocks the light source to determine the pattern of the photoresist 202 to be radiated. In a non-contact mode, the pattern of the photomask 210 is transferred to the photoresist 202 by the lens set 214. The fabrication of the conventional photomask is very time consuming and costly. The photomask has to be kept in an appropriate environment, and the maintenance cost is also high.
In addition, the pattern of the photomask cannot be modified. When the circuit design of the wafer or printed circuit board requires a modification, a new photomask has to be fabricated.
The present invention provides a substrate exposure apparatus and method that does not require a photomask. The fabrication cost and maintenance cost of a photomask in the photolithography process are thus saved.
The substrate exposure apparatus provided by the present invention comprises a scan light source and a control system. The scan light source is located over the photoresist to be exposed on the substrate. The control system controls the scan light source or the substrate to shift along a scan path, and converts the pattern to be formed on the photoresist into a timing signal, so as to control the light and dark status of the scan light source at different times.
In the above substrate exposure apparatus, the scan light comprises multiple point light sources. The point light sources are arranged in a single file such as a line light source. Alternatively, the point light sources can be arranged in multiple files such as multiple line light sources. The line light sources are parallel to each other. Along the aligning direction of each line light source, there is a specific position shift for each of the line light sources, so that the point light sources in one line light source are staggered with the point light sources in another line light source. As a result, the exposure resolution is enhanced. The above point light sources include light emitting diodes and laser diodes.
In the substrate exposure apparatus of the present invention, the light of the scan light source is adjusted by a lens set to radiate the photoresist for exposure.
In the present invention, a substrate exposure method is provided. The substrate exposure method uses a scan light source and a control system to perform exposure on a photoresist on a substrate. The scan light source is located above the photoresist. The control system controls the scan light source or the substrate to shift along a scan path. The pattern to be transferred to the photoresist is converted into a timing signal to control the light and dark status of the scan light source, so as to perform exposure on the photoresist.
In the above substrate exposure method, the scan path of the scan light source is vertical to the aligning direction of the point light sources.
In the above substrate exposure method, the scan path of the scan light does not have to be vertical to the aligning direction of the point light sources.
Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.